Click on a day for an hourly weather forecast
The temperatures in Key Largo during September are extremely high, between 28°C and hot as 29°C, drinking water regularly is advisable.
You can expect rain for roughly half of the month of September in Key Largo. We’re expecting roughly 8 to 15 days of rain, so your rubber boots and umbrella are going to see plenty of use this month if you’re keen on staying dry.
Our weather forecast can give you a great sense of what weather to expect in Key Largo in September 2025.
If you’re planning to visit Key Largo in the near future, we highly recommend that you review the 14 day weather forecast for Key Largo before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 22° / 20° | 2 | 29 | 0 | 51 mm | Good | Key Largo in January |
| February | 23° / 21° | 3 | 26 | 0 | 51 mm | Perfect | Key Largo in February |
| March | 24° / 22° | 2 | 29 | 0 | 38 mm | Perfect | Key Largo in March |
| April | 25° / 24° | 3 | 27 | 0 | 82 mm | Perfect | Key Largo in April |
| May | 27° / 25° | 7 | 24 | 0 | 139 mm | Good | Key Largo in May |
| June | 29° / 27° | 11 | 19 | 0 | 219 mm | Ok | Key Largo in June |
| July | 29° / 28° | 12 | 19 | 0 | 227 mm | Ok | Key Largo in July |
| August | 30° / 28° | 14 | 17 | 0 | 287 mm | Ok | Key Largo in August |
| September | 29° / 28° | 13 | 17 | 0 | 283 mm | Ok | Key Largo in September |
| October | 28° / 26° | 7 | 24 | 0 | 198 mm | Good | Key Largo in October |
| November | 25° / 24° | 3 | 27 | 0 | 82 mm | Perfect | Key Largo in November |
| December | 24° / 22° | 2 | 29 | 0 | 60 mm | Perfect | Key Largo in December |